95 lines
3.5 KiB
C++
95 lines
3.5 KiB
C++
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// Ceres Solver - A fast non-linear least squares minimizer
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// Copyright 2015 Google Inc. All rights reserved.
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// http://ceres-solver.org/
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are met:
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//
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// * Redistributions of source code must retain the above copyright notice,
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// this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above copyright notice,
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// this list of conditions and the following disclaimer in the documentation
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// and/or other materials provided with the distribution.
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// * Neither the name of Google Inc. nor the names of its contributors may be
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// used to endorse or promote products derived from this software without
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// specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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// POSSIBILITY OF SUCH DAMAGE.
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//
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// Author: sameeragarwal@google.com (Sameer Agarwal)
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//
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// A simple example of optimizing a sampled function by using cubic
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// interpolation.
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#include "ceres/ceres.h"
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#include "ceres/cubic_interpolation.h"
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#include "glog/logging.h"
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using ceres::Grid1D;
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using ceres::CubicInterpolator;
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using ceres::AutoDiffCostFunction;
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using ceres::CostFunction;
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using ceres::Problem;
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using ceres::Solver;
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using ceres::Solve;
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// A simple cost functor that interfaces an interpolated table of
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// values with automatic differentiation.
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struct InterpolatedCostFunctor {
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explicit InterpolatedCostFunctor(
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const CubicInterpolator<Grid1D<double> >& interpolator)
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: interpolator_(interpolator) {
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}
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template<typename T> bool operator()(const T* x, T* residuals) const {
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interpolator_.Evaluate(*x, residuals);
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return true;
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}
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static CostFunction* Create(
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const CubicInterpolator<Grid1D<double> >& interpolator) {
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return new AutoDiffCostFunction<InterpolatedCostFunctor, 1, 1>(
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new InterpolatedCostFunctor(interpolator));
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}
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private:
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const CubicInterpolator<Grid1D<double> >& interpolator_;
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};
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int main(int argc, char** argv) {
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google::InitGoogleLogging(argv[0]);
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// Evaluate the function f(x) = (x - 4.5)^2;
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const int kNumSamples = 10;
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double values[kNumSamples];
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for (int i = 0; i < kNumSamples; ++i) {
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values[i] = (i - 4.5) * (i - 4.5);
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}
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Grid1D<double> array(values, 0, kNumSamples);
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CubicInterpolator<Grid1D<double> > interpolator(array);
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double x = 1.0;
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Problem problem;
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CostFunction* cost_function = InterpolatedCostFunctor::Create(interpolator);
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problem.AddResidualBlock(cost_function, NULL, &x);
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Solver::Options options;
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options.minimizer_progress_to_stdout = true;
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Solver::Summary summary;
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Solve(options, &problem, &summary);
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std::cout << summary.BriefReport() << "\n";
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std::cout << "Expected x: 4.5. Actual x : " << x << std::endl;
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return 0;
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}
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